A128661 Numbers k such that p(k+1)# + p(k)# - p(k-1)# - 1 is prime where p(i)# = product of first i primes = A002110(i).
3, 7, 14, 15, 21, 32, 34, 47, 67, 69, 174, 369, 568, 3193, 3882, 5426
Offset: 1
Programs
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Mathematica
Flatten[Position[Partition[Rest[FoldList[Times,1,Prime[Range[ 600]]]],3,1], ?(PrimeQ[#[[3]]+#[[2]]-#[[1]]-1]&),{1},Heads-> False]]+1 (* _Harvey P. Dale, May 26 2013 *)
Extensions
a(14)-a(16) from Michael S. Branicky, Jul 22 2023